This study develops and tests a general model of health behavior with specific application to pregnancy related health behavior. The general model is an extension and revision of the Health Belief Model and incorporates the social and structural contexts in which the decision to engage in a health behavior is made. The principle components of this model are: normative expectations to perform the behavior, access to resources, health status, saliency and the perceived costs and perceived benefits of engaging in health behaviors. A multiple indicators, causal model approach is used. The data are obtained by questionnaires and telephone interviews. The health behavior of pregnant women was selected to test the general model not only because of its general importance, but also because of an extensive literature linking both health services and personal health maintenance to the health of pregnant women and their infants--thus providing a solid foundation for the formulation of a causal model and the specification of indicators and measures.